This proposal requests funds to purchase a Zeiss LSM 5 confocal microscope to be utilized by an interactive group of four NIH-funded investigators in the Department of Physiology and Neuroscience Program at Michigan State University. The major research topics include synaptic function of spinal neurons, mechanisms of glaucoma-induced degeneration in the visual system, role of cell-surface glycoproteins in neuronal development, and autonomic regulation of vasculature. Confocal microscopy is an essential tool of the funded projects, which make use of intracellular labeling and fluorescence immuno- cytochemistry in aldehyde-fixed tissue sections and whole-mount preparations. The LSM 5 is a mid-priced, bench-top instrument that will fill a critical need for high resolution imaging of multiple fluorophores in single tissue sections and three dimensional analyses of neuronal structure. The LSM 5 will provide: 1) two laser excitation lines at 488nm and 543nm for imaging green and red fluorophores, 2) sequential control of laser line output and detection channels to significantly reduce signal cross-talk, 3) automated, continuously variable confocal aperture, 4) optical sectioning in xy and xz planes, and 5) computer-generated `side- views' (xz and yz) of structures at any location within an image stack. The instrument will permit the investigators to perform efficient two- color analyses of subcellular structures and neuronal imaging not possible now at the institution. To promote maintenance and foster equitable use, the instrument will be integrated into the Laser Scanning Microscope Laboratory, an established University core facility with a nine-year track record serving the confocal microscopic needs of researchers. The University will provide significant institutional support for the instrument in the form of space allocation, salary for the Laboratory Director and staff, who will supervise its operation and provide technical assistance to the major users. Acquisition of the LSM 5 will significantly enhance the research programs of the major users and aid other investigators in the broader MSU research community.